GR Silver begins 20,000 m drill program at Plomosas

Executive Summary

• GR Silver Mining has commenced a 20,000-metre step-out drilling campaign at the San Marcial area of its Plomosas silver project, aiming to expand the mineral resource base ahead of a planned resource update and preliminary economic assessment in late 2026.
• The company has relocated its exploration office from Sinaloa to Durango to mitigate security risks and ensure operational continuity, while mobilizing multiple drill rigs to the site.
• The drilling program targets significant resource growth, including extending mineralization along strike by 200 metres, defining boundaries to 400 metres depth, and exploring a newly discovered parallel breccia zone with high-grade intersections.

Key Details

• Drilling Program Scope: 20,000 metres of surface step-out drilling in the San Marcial area; represents a 100% increase in metres drilled outside the current NI 43-101 resource area.
• Timeline: Program expected to complete early in the second half of 2026; mineral resource update and preliminary economic assessment planned for late 2026.
• Resource Expansion Objectives:
  • Expand silver-mineralized system footprint by an additional 200 metres along strike.
  • Define boundaries of silver mineralization to shallow depths of up to 400 metres below surface.
  • Drill at an anticipated hole spacing of 70 metres.
  • Grow mineral resources by adding silver ounces in high-grade primary content zones.
  • Expand footprint along strike and downdip of the recently discovered parallel breccia zone.
• Recent High-Grade Intersections (Context for 2025 Campaign):
  • SMS25-09: 75 metres at 260 grams per tonne silver (g/t Ag).
  • SMS 25-10A: 9 metres at 374 g/t Ag, including an associated gold discovery of 1 metre at 32.1 grams per tonne gold (g/t Au).
• Operational Changes: Exploration office relocated to Durango, Mexico, to manage access to the Plomosas project and address security challenges in Sinaloa; relocation initiated in late 2025.
• Permits: Program leverages a recently granted five-year surface drilling permit.
• QA/QC Procedures: Samples assayed at SGS de Mexico SA de CV in Durango; overlimit silver samples (>100 ppm) reassayed using lead fusion fire assay and gravimetric finish; gold assays use lead fusion fire assay and atomic absorption spectrometry.

Notable Quotes

• "Two thousand twenty-six is expected to be a pivotal year for GR Silver Mining as the company leverages the five-year drilling permit obtained last year, together with its strong financial position, to advance resource growth at San Marcial." — Marcio Fonseca, President and CEO